Landowners at Ginninderra Falls say their property is being invaded by carloads of people keen for a swim and they are struggling to keep the trespassers out.
It comes just a week after the dramatic rescue of a teenager injured while trespassing in the area.
He was treated at the scene by paramedics, who swam across the creek to reach him and then swam him back to safety on a stretcher.
The teen was then handed over to vertical rescue firefighters, who spent several hours winching him up the cliff.
The fall happened at 7:00pm and much of the rescue was carried out in the dark.
14 'carloads' sighted at Ginninderra Falls Ginninderra Falls sit just over the northern border of the ACT in New South Wales, near land earmarked for future residential development as part of the new suburb of West Belconnen.
The Hyles family, which owns the land around the falls, once maintained them for public access, but the area was closed in 2004 over liability concerns.
There are plans in the pipeline to open Ginninderra Falls as a green offset for the development, which would be managed by a conservation trust.
Riverview Projects director David Maxwell, whose company is managing the development, said progress was being made.
But with more planning hurdles to be overcome, the final approval for the development - and for the re-opening of the falls - is unlikely to happen before early 2017.
In the meantime, locals impatient for the falls to be re-opened have been trespassing to gain access.
Last week, landowner Anna Hyles told the ABC that on the day the boy was rescued there were 14 cars parked at the gate to falls.
"That's not 14 people, that's 14 carloads of people," Mrs Hyles said.
"And that's one hot day. You've then got the whole summer holidays."
Mrs Hyles said she was keen to open the falls to the public but right now, with no safety measures in place, it simply was not practical.
"They're having little bonfires and sitting around drinking... then you have the issue that it's a hot day and fire breaks out," she said.
"It's a bigger issue than just people tripping and hurting themselves."
Other landowners threatened by trespassers
Damon Cusack from the Ginninderra Catchment Management Group said his organisation was working with the landowners, the property developer and the Ginninderra Falls Association to make public access possible.
Mr Cusack said it was not just the Hyles who were experiencing problems with trespassers.
"There have been other landowners that have had some minor altercations with people who've been accessing... and some minor threats to them," he said.
"I think there's been some suggestion that paddocks might be burnt if they don't keep their nose out of it. That tends to be a little bit confronting to landowners."
The falls are in NSW, but responsibility for policing the area is shared by NSW and ACT police.
NSW Police Inspector Rob Post, from the Hume Local Area Command, said people who visited the falls without permission from the landowner were trespassing and could be prosecuted by police.
"If people enter enclosed lands without the permission of the owner or the proper authority, police can take action in relation to that and people can be sent to court and issued with a fine or other sorts of sanctions," he said.
"We do have problems regularly in relation to private property and police do quite often put those matters before the court."
The Hyles said they had contacted ACT Roads and Transport about the problem and more signs were to be erected on the road warning the land was not accessible to the public.
Mrs Hyles's husband, John, said the falls were spectacular and he understood the public's desire to visit.
"There's no reason why it can't all be done again. Safely," he said.
The Hyles said they were committed to reopening the falls and urged people to be patient until that happened.
"The intention is when the suburb of West Belconnen is built... this will be open to the public, and it will be a sustainable tourist development," Mr Hyles said.